Orchestration describes the automated arrangement, coordination, and management of complex computer systems, middleware, and services. This usage of orchestration is often discussed in the context of service oriented architecture, virtualization, provisioning, converged infrastructure, and dynamic datacenter topics. Orchestration in this general sense can include aligning the business request with the applications, data, and infrastructure. It defines the policies and service levels through automated workflows, provisioning, and change management. This creates an application-aligned infrastructure that can be scaled up or down based on the needs of each application. Orchestration also provides centralized management of the resource pool, including billing, metering, and chargeback for consumption.